Peppermint oil may temporarily act as a rat and mouse deterrent in your home or property. Peppermint oil is generally thought to be safer than other chemical deterrents, but in some instances, it may be poisonous to pets, especially cats.
Pure peppermint oil sold in aromatherapy suppliers and health food stores is more effective than diluted peppermint oil or peppermint scented oil used for oil lamps; the latter types will not deter rats or mice.
Soak cotton balls or rags with peppermint oil and leave them where you suspect the mice or rats are hiding. Also, make a spray of peppermint oil and water to use outside in the garden. Refresh the spray or cotton balls with more oil every few days for rats and every two weeks for mice.
Peppermint oil will not deter squirrels, but planting peppermint plants can. These plants also can deter rats and mice from gardens.
Peppermint oil and peppermint plants can be toxic to cats. If you have cats, do not use peppermint products for rodent control.